Recently, micro base station apparatuses (home base station: Home eNB, hereinafter HeNB) to form small cells have been developed for complementing dead zones of mobile phone networks. The small cell is referred to as a femto cell, covering a smaller communication area than one conventional cell. Conventional large base station apparatuses to form cells having large communication areas (Macro base station: Macro eNB, hereinafter referred to as an MeNB) are set beforehand through an appropriate design of placement of stations by operators. Interference between cells does not make a significant problem owing to an ICIC (Inter Cell Interference Coordination) control function between the MeNBs. In contrast with this, end users can set HeNBs in any place and there is no ICIC control function between the HeNB and the MeNB. Interference between the HeNB and the MeNB therefore makes a significant problem in HeNB. Especially, the placement of the HeNB should not interfere with the communications of any existing MeNB. This is because the MeNB is used for forming an existing communication area, for example, for mobile phone networks, and it is necessary to avoid inconvenience such as sudden disconnection of the mobile phones caused by a newly placed HeNB.
With LTE (Long Term Evolution) which has been standardized by international standards organization 3GPP (3rd Generation Partnership Project), subbands allocated to the HeNB are scheduled in a frequency band (including a plurality of subbands) available for the HeNB (see, for example, Non-patent Literature 1). The HeNB assigns subbands based on the resulting schedule and communicates with a communication terminal apparatus (hereinafter, referred to as HUE: Home UE) connected to the HeNB.
With LTE, MeNBs (surrounding MeNBs) are connected to each other by an X2 interface. Each eNB (an MeNB and an HeMB), and an MME (Mobility Management Entity)/S-GW (Serving Gateway) or an HeNB GW are connected by an S1 interface (see, for example, Non-Patent Literature 2). By contrast with this, LTE has no interface directly connecting the MeNB and the HeNB.